A scheme for nonreciprocal mechanical squeezing (NMS) based on the three‐mode optomechanical interaction is proposed. In this scheme, a mechanical mode couples to a spinning whispering‐gallery‐cavity (WGC) mode and to an optical mode. An external laser is coupled into and thus drives the WGC via a waveguide. Mechanical squeezing results from the joint effect of the mechanical intrinsic nonlinearity and the quadratic optomechanical coupling, which, in the presence of strong thermal noise, is still considerable, while the nonreciprocity originates from the optical Sagnac effect. There are two NMS areas in the parametric space, one works for the laser driving from the left of the waveguide and another, from the right. For a given spinning speed of the WGC, the squeezing values in these two areas are equal if the corresponding detunings of the WGC differ from each other by two‐times of the Sagnac–Fizeau shift. At the red‐detuning resonance, the analytical results for the mechanical squeezing and cooling are obtained. The NMS scheme is robust to the thermal noise of the mechanical environment.

中文翻译：

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旋转光机械系统中的不可逆机械挤压

提出了一种基于三模光机械相互作用的不可逆机械挤压（NMS）方案。在此方案中，机械模式耦合到旋转的耳语画廊腔（WGC）模式和光学模式。外部激光器耦合到WGC中，并因此通过波导驱动WGC。机械挤压是由机械固有非线性和二次光机耦合的联合效应引起的，在强烈的热噪声存在下，二次光机耦合仍然是相当大的，而不可逆性则源于光学Sagnac效应。参数空间中有两个NMS区域，一个区域用于从波导左侧驱动激光，另一个区域从右侧驱动激光。对于WGC的给定旋转速度，如果WGC的相应失谐彼此相差两次Sagnac-Fizeau偏移，则这两个区域中的压缩值相等。在红色失谐共振处，获得了机械挤压和冷却的分析结果。NMS方案对机械环境的热噪声具有鲁棒性。